[期刊论文][Full-length article]


Structural dimension gradient design of oxygen framework to suppress the voltage attenuation and hysteresis in lithium-rich materials

作   者:
Zhe Yang;Jianjian Zhong;Jiameng Feng;Jianling Li;Feiyu Kang;

出版年:2022

D  O  I:10.1016/j.cej.2021.130723

页    码:130723 - 130723
出版社:Elsevier BV


摘   要:

As a cathode material for lithium-ion batteries with the highest capacity (>280 mAh g−1) in the intercalated lithium storage mode, lithium-rich layered oxides still suffer from capacity decay, voltage attenuation and hysteresis caused by the unstable O evolution. In this work, Os surface doping has been applied to Li1.2Ni0.13Co0.13Mn0.54O2 for structural dimension gradient design of oxygen framework, inducing a surface heterostructure with three-dimensional Li/transition metal (TM) cations disorder. The octahedral coordination environment of surface oxygen transforms into a random and disordered distribution of Li/TM, differing from the two-dimensional ordered oxygen framework configuration inside the bulk. This promotes the three-dimensional disordered arrangement of O 2p unhybridized orbitals, and reduces the coplanar probability of those between adjacent O elements, thus effectively inhibiting the generation of O-O dimers under high voltage condition and the loss of surface oxygen. The high-stable interface alleviates the side reaction with electrolyte and the densification of structure, improves the Li+ diffusion migration kinetics and reduces the overpotential. Meanwhile, the occupancy and migration path of Li+ on the surface layer transforms from two-dimensional order into three-dimensional disorder, which changes the thermodynamic reaction potential. The electrochemical performance particularly voltage attenuation and hysteresis are significantly improved by 2 at% Os doping. The average voltage attenuation per cycle is reduced by more than half from 2.17 mV to 1.01 mV during 300 cycles, and the voltage hysteresis between charge and discharge is reduced from 1.228 V to 0.733 V at the 300th cycle. This provides an idea for studying the mechanism of coordination environment of oxygen and the migration path of Li+ for cathode materials.



关键字:

Li-ion battery ; Lithium-rich layered oxides ; Voltage attenuation and hysteresis ; Structural dimension ; Surface doping


所属期刊
Chemical Engineering Journal
ISSN: 1385-8947
来自:Elsevier BV